(This article first appeared in the NEC Newsletter, published by the New England Coalition on Nuclear Pollution.)
Biogas is a natural product of anaerobic fermentation. It is produced in waste facilities, in landfills, and as agricultural waste. Unlike wood gas, it will be produced, whether we intend to use it or not. Our choice is not to use it or not use it. Our choice is to use it or let it go into the environment.
It is important to use biogas. In fact, we would do less damage to the environment by trapping it and burning it, without any economic benefit, than just letting it go into the atmosphere. The reason for this is that biogas consists largely of methane, and methane is over twenty times as powerful as carbon dioxide in its contribution to global warming. Fortunately, we can derive benefit from it. And because using biogas for power generation will have a positive effect on global warming, we can feel good about it as well.
Biogas can have some problems, for instance if the waste it is made from has certain chemicals in it. It can have siloxanes, if the waste has soap in it, as would probably be the case in sewage. Siloxanes burn to produce silicates, which are not very kind to the generating engines. Fortunately, modern technology can remove these.
Biogas production is already underway. The last time I checked on this, biogas from a landfill owned by the Vermont Energy Cooperative was producing power at the lowest wholesale rate available in Vermont.